The standard mattress is generally comprised of upper and lower border wires which extend about the perimeter portion of the mattress; a plurality helical support springs disposed throughout the mattress, the outermost springs being secured at their upper and lower ends to the border wires; one or more layers of padding disposed over the springs and a covering material. While this construction provides comfortable and adequate support for persons lying on the mattress, it provides little or no support about the edge portions thereof. Consequently, when a person sits on or near the edge of the mattress, the supporting structure is stressed and deformed to such an extend that repeated sitting will result in damage to the structural elements of the mattress.
To increase the structural support of mattresses about the edge portions thereof, a new mattress was developed which included a third border wire disposed between the upper and lower wires, which as with the upper and lower wires is held by the outermost helical supporting springs. This structure which is the subject of U.S. Letters Pat. No. 3,256,535, while adding some additional structural strength to the edge portions of a mattress, is nevertheless lacking in sufficient strength to adequately support a person sitting on the edge of a mattress. As a result, repeated sitting on the mattress has still been found to cause deterioration of the edge portions thereof. In view of the fact that people will continue to sit on mattresses, regardless of any warnings by the manufacturers thereof, it would be highly desirable to provide a simple and economical stiffener which could be secured at the various locations about the edge portions of the mattress to provide those portions with sufficient strength to support a person sitting thereon and thereby prevent the aforesaid deterioration of the mattress.